1. Field of the Invention
This invention relates to a method and device for measuring magnetic fields whereby a magnetically sensitive probe is introduced into a magnetic field to be measured and transmits a signal to a measuring device for evaluation.
2. Description of the Prior Art
The technique for measuring magnetic fields using Hall probes is known from the literature. For example, the firm of List-Magnetik GmbH, D-7022 Leinfelden-Echterdingen offers such a portable magnetic field measuring device under the name of MP-U. This device is suitable for measuring time-constant fields in both directions of polarity (north and south pole), and selectively also for measuring alternating fields. As operating elements, the device has respectively one selection switch for the type of display (constant or alternating field, as well as peak value memory) and the measuring range, a key for resetting the peak value indication and a rotating knob for setting the zero point.
A similar device is offered by the firm of Walker Scientific Inc., Worcester, Mass., USA, under the model designation MG-5DP. This device also has essentially the same operating elements: a function selector, a measuring range selector, a peak value reset key and a zero point setting knob. As with the first mentioned device, a digital display is disposed at the front face of the measuring device. The magnetic field probe is connected to the device by a cable.
In actual, use these measuring devices are uncomfortable to handle and complicated to operate. Often the setting of the zero point is omitted when activating the device. This causes continuously faulty readings if subsequently the zero point setting is inadvertently changed.
The selection of the measuring range requires an intervention at the measuring device which distracts from the actual measuring task. Areas having different field strengths are again and again contacted, especially in the course of diagnosing magnetic fields, which always requires a correction of the measuring range. For peak value measurement, the magnitude of the value must be known in order to use the indicator.
The measurement of magnetic fields requires the continuous correlation of the probe position and the measured value. This, in turn requires alternating observation of the probe and the display.